What changed between consecutive top-of-book messages (AAPL, 10:00 to 10:30 a.m. ET, June 16, 2026)
Answered against 22 years of US equities and 12 years of US options data and published with the query that produced it. This result is stored as of 2026-08-12, from MBO vs MBP Order Book Data Explained.
| message_type | message_count | share_pct |
|---|---|---|
| best bid price changed | 20177 | 17.6 |
| size joined at the best bid | 19996 | 17.4 |
| size left the best bid | 13730 | 12 |
| bid untouched, ask side updated | 60887 | 53 |
- Rows × columns
- 4 × 3
- Computed
- Completeness
- No missing values
- Source
- US exchange, SIP and OPRA market data
- Licence
- Strasmore terms · free, no signup
What each column holds
| Column | Type | Range | Notes |
|---|---|---|---|
message_type |
text | 4 distinct values | |
message_count |
number | 13,730 to 60,887 | count |
share_pct |
number | 12 to 53 | percent |
Computed from Strasmore's warehouse of US exchange, SIP and OPRA market data. Equity prices are delayed; options greeks and implied volatility are end-of-day. This result is stored, not recomputed on load — it is exactly the numbers that were returned on , and the query below is what returned them.
the exact SQL behind every number
WITH
ordered AS
(
SELECT
row_number() OVER (ORDER BY sip_timestamp, sequence_number) AS msg_index,
bid_price,
bid_size,
lagInFrame(bid_price) OVER (ORDER BY sip_timestamp, sequence_number) AS prev_bid_price,
lagInFrame(bid_size) OVER (ORDER BY sip_timestamp, sequence_number) AS prev_bid_size
FROM global_markets.cache_stocks_quotes
WHERE ticker = 'AAPL'
AND sip_timestamp >= '2026-06-16 14:00:00'
AND sip_timestamp < '2026-06-16 14:30:00'
AND bid_price > 0
),
classified AS
(
SELECT multiIf(
bid_price != prev_bid_price, 'best bid price changed',
bid_size > prev_bid_size, 'size joined at the best bid',
bid_size < prev_bid_size, 'size left the best bid',
'bid untouched, ask side updated') AS message_type
FROM ordered
WHERE msg_index > 1
)
SELECT
message_type,
count() AS message_count,
round(100 * count() / sum(count()) OVER (), 1) AS share_pct
FROM classified
GROUP BY message_type
ORDER BY indexOf(['best bid price changed', 'size joined at the best bid', 'size left the best bid', 'bid untouched, ask side updated'], message_type)
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